Narcotics investigators in Oklahoma have announced a public warning about deadly counterfeit oxycodone made with fentanyl that has killed at least one Oklahoma resident,KFOR public radio reports.

Oklahoma State Bureau of Investigation (OSBI) spokesman Mark Woodward told KFOR "We don’t know how widespread these pills might be. People need to understand they don’t know what they’re buying. It could be oxycodone diverted out on the streets, or something pressed to look like oxycodone."

Woodward toldKTEN that “It was blue, stamped the same as an OxyContin, but the OSBI state crime lab test confirmed that it was actually fentanyl.”

KTUL notes that a second person was also poisoned by the counterfeit pills but was revived after treatment with Narcan.

Authorities have asked that anyone with pertinent information to the investigation should call OBN at 800-522-8031. Callers can remain anonymous.